![KAMEZAWA Hiroyuki](/assets/img/avatar_default.png)
In /proc/stat, the number of per-IRQ event is shown by making a sum each irq's events on all cpus. But we can make use of kstat_irqs(). kstat_irqs() do the same calculation, If !CONFIG_GENERIC_HARDIRQ, it's not a big cost. (Both of the number of cpus and irqs are small.) If a system is very big and CONFIG_GENERIC_HARDIRQ, it does for_each_irq() for_each_cpu() - look up a radix tree - read desc->irq_stat[cpu] This seems not efficient. This patch adds kstat_irqs() for CONFIG_GENRIC_HARDIRQ and change the calculation as for_each_irq() look up radix tree for_each_cpu() - read desc->irq_stat[cpu] This reduces cost. A test on (4096cpusp, 256 nodes, 4592 irqs) host (by Jack Steiner) %time cat /proc/stat > /dev/null Before Patch: 2.459 sec After Patch : .561 sec [akpm@linux-foundation.org: unexport kstat_irqs, coding-style tweaks] [akpm@linux-foundation.org: fix unused variable 'per_irq_sum'] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Jack Steiner <steiner@sgi.com> Acked-by: Jack Steiner <steiner@sgi.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
127 lines
3 KiB
C
127 lines
3 KiB
C
#ifndef _LINUX_KERNEL_STAT_H
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#define _LINUX_KERNEL_STAT_H
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#include <linux/smp.h>
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#include <linux/threads.h>
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#include <linux/percpu.h>
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#include <linux/cpumask.h>
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#include <linux/interrupt.h>
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#include <asm/irq.h>
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#include <asm/cputime.h>
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/*
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* 'kernel_stat.h' contains the definitions needed for doing
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* some kernel statistics (CPU usage, context switches ...),
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* used by rstatd/perfmeter
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*/
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struct cpu_usage_stat {
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cputime64_t user;
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cputime64_t nice;
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cputime64_t system;
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cputime64_t softirq;
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cputime64_t irq;
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cputime64_t idle;
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cputime64_t iowait;
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cputime64_t steal;
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cputime64_t guest;
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cputime64_t guest_nice;
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};
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struct kernel_stat {
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struct cpu_usage_stat cpustat;
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#ifndef CONFIG_GENERIC_HARDIRQS
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unsigned int irqs[NR_IRQS];
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#endif
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unsigned long irqs_sum;
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unsigned int softirqs[NR_SOFTIRQS];
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};
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DECLARE_PER_CPU(struct kernel_stat, kstat);
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#define kstat_cpu(cpu) per_cpu(kstat, cpu)
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/* Must have preemption disabled for this to be meaningful. */
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#define kstat_this_cpu __get_cpu_var(kstat)
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extern unsigned long long nr_context_switches(void);
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#ifndef CONFIG_GENERIC_HARDIRQS
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#define kstat_irqs_this_cpu(irq) \
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(kstat_this_cpu.irqs[irq])
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struct irq_desc;
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static inline void kstat_incr_irqs_this_cpu(unsigned int irq,
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struct irq_desc *desc)
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{
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kstat_this_cpu.irqs[irq]++;
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kstat_this_cpu.irqs_sum++;
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}
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static inline unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
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{
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return kstat_cpu(cpu).irqs[irq];
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}
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#else
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#include <linux/irq.h>
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extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu);
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#define kstat_irqs_this_cpu(DESC) \
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((DESC)->kstat_irqs[smp_processor_id()])
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#define kstat_incr_irqs_this_cpu(irqno, DESC) do {\
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((DESC)->kstat_irqs[smp_processor_id()]++);\
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kstat_this_cpu.irqs_sum++; } while (0)
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#endif
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static inline void kstat_incr_softirqs_this_cpu(unsigned int irq)
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{
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kstat_this_cpu.softirqs[irq]++;
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}
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static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
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{
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return kstat_cpu(cpu).softirqs[irq];
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}
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/*
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* Number of interrupts per specific IRQ source, since bootup
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*/
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#ifndef CONFIG_GENERIC_HARDIRQS
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static inline unsigned int kstat_irqs(unsigned int irq)
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{
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unsigned int sum = 0;
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int cpu;
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for_each_possible_cpu(cpu)
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sum += kstat_irqs_cpu(irq, cpu);
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return sum;
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}
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#else
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extern unsigned int kstat_irqs(unsigned int irq);
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#endif
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/*
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* Number of interrupts per cpu, since bootup
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*/
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static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
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{
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return kstat_cpu(cpu).irqs_sum;
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}
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/*
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* Lock/unlock the current runqueue - to extract task statistics:
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*/
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extern unsigned long long task_delta_exec(struct task_struct *);
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extern void account_user_time(struct task_struct *, cputime_t, cputime_t);
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extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t);
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extern void account_steal_time(cputime_t);
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extern void account_idle_time(cputime_t);
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extern void account_process_tick(struct task_struct *, int user);
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extern void account_steal_ticks(unsigned long ticks);
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extern void account_idle_ticks(unsigned long ticks);
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#endif /* _LINUX_KERNEL_STAT_H */
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